Imaging device having an optical image stabilizer

ABSTRACT

An imaging device is provided, including a photographing optical system including an image sensor positioned at an imaging position of the photographing optical system, and an image stabilizer which detects vibration applied to the photographing optical system and moves the image sensor in a plane orthogonal to an optical axis of the photographing optical system to counteract image shake in accordance with a direction and a magnitude of the vibration. The image sensor and a rearmost lens group of the photographing optical system, which is positioned in front of the image sensor, are provided as a movable unit so that the image sensor and the rearmost lens group are integrally moved by the image stabilizer.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an imaging device, more specificallyrelates to an imaging device having an optical image stabilizer forcounteracting image shake due to vibrations such as hand shake (camerashake).

2. Description of the Related Art

Imaging devices such as cameras which come with image stabilization orvariants such as anti-shake for preventing image shake from occurring onan imaging surface when vibrations such as hand shake is applied to theimaging device are in practical use. Specifically, among digital camerasusing a CCD or CMOS image sensor as an image capturing medium, digitalcameras having an optical image stabilizer have been in the mainstreamin recent years. In this type of digital camera, the image sensor ismoved in a plane orthogonal to a photographing optical axis tocounteract image shake.

In digital cameras, the photographing optical system needs to bedesigned as an image-side telecentric optical system due to thecharacteristics of the image sensor, and therefore, the effectiveaperture of the rearmost lens group positioned immediately in front ofthe image sensor tends to be large. For this reason, if the image sensoris made to be movable in a plane orthogonal to a photographing opticalaxis, a further increase in effective aperture of the rearmost lensgroup is required, which may increase the size of the digital camera.

Additionally, the image sensor is made to have a dust-proof structure toprevent dust from sticking to a light-receptive surface (imagingsurface) of the image sensor, and hence, simplification of the structureof the imaging device including the dust-proof structure is desirable.

SUMMARY OF THE INVENTION

The present invention provides an imaging device having an optical imagestabilizer, wherein the structure of the image sensor on the peripherythereof is simple, thus making it possible to achieve a miniaturizationof the imaging device.

According to an aspect of the present invention, an imaging device isprovided, including a photographing optical system including an imagesensor positioned at an imaging position of the photographing opticalsystem, and an image stabilizer which detects vibration applied to thephotographing optical system and moves the image sensor in a planeorthogonal to an optical axis of the photographing optical system tocounteract image shake in accordance with a direction and a magnitude ofthe vibration. The image sensor and a rearmost lens group of thephotographing optical system, which is positioned in front of the imagesensor, are provided as a movable unit so that the image sensor and therearmost lens group are integrally moved by the image stabilizer.

It is desirable for the rearmost lens group and the image sensor to beheld by a common holder in a dust-resistant fashion so that adust-resistant space is formed between the rearmost lens group and theimage sensor with a light-receptive surface of the image sensor beingpositioned in the dust-resistant space.

It is desirable for the photographing optical system to include a filterpositioned in the common holder between the rearmost lens group and theimage sensor.

It is desirable for the imaging device to include a first moving framewhich holds the common holder and is movable linearly in a firstdirection in the plane that is orthogonal to the optical axis, and asecond moving frame which holds the first moving frame and is movablelinearly in a second direction perpendicular to the first direction inthe plane that is orthogonal to the optical axis.

It is desirable for the imaging device to include a radially-retractingdevice which moves the movable unit to a radially-retracted position, atwhich the movable unit is radially retracted away from the optical axisalong a direction perpendicular to the optical axis beyond apredetermined range of movement of the movable unit for imagestabilization, when the imaging device changes from a photographic stateto a non-photographing state.

When the movable unit is at the radially-retracted position, anotheroptical element of the photographing optical system can enter a space inwhich the movable unit is positioned when at a photographing position atwhich the movable unit is located on the optical axis in thephotographic state.

It is desirable for the other optical element to be positioned in frontof the movable unit on the optical axis in the photographic state.

In an embodiment, an imaging device is provided, including aphotographing optical system including an image sensor positioned behinda rearmost lens group of the photographing optical system, the rearmostlens group and the image sensor being provided as a movable unit so thatthe image sensor and the rearmost lens group are integrally movable in aplane orthogonal to an optical axis of the photographing optical system;a detector for detecting vibration applied to the photographing opticalsystem; and an actuator which moves the movable unit in the plane tocounteract image shake in accordance with a direction and a magnitude ofthe vibration detected by the detector.

The present disclosure relates to subject matter contained in JapanesePatent Application No.2004-349192 (filed on Dec. 1, 2004) which isexpressly incorporated herein by reference in its entirety.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be described below in detail with referenceto the accompanying drawings in which:

FIG. 1 is a cross-sectional view of an embodiment of a retractable zoomlens to which the present invention is applied in the retracted state ofthe zoom lens barrel;

FIG. 2 is a cross-sectional view of the zoom lens shown in FIG. 1 in aphotographic state of the zoom lens;

FIG. 3 is an enlarged cross-sectional view of a part of the zoom lens atthe wide-angle extremity thereof;

FIG. 4 is an enlarged cross-sectional view of a part of the zoom lens atthe telephoto extremity thereof;

FIG. 5 is a block diagram illustrating a configuration of electricalcircuits of a camera equipped with the zoom lens shown in FIGS. 1 and 2;

FIG. 6 is a conceptual diagram showing the moving paths of a helicoidring and a cam ring and the moving paths of a first lens group and asecond lens group by movement of the cam ring;

FIG. 7 is a conceptual diagram showing the combined moving path of eachof the first lens group and the second lens group, in which the movingpaths of the helicoid ring and the cam ring are included;

FIG. 8 is an exploded perspective view of the zoom lens shown in FIGS. 1and 2;

FIG. 9 is an exploded perspective view of elements of an imagestabilizing mechanism and a radially-retracting mechanism which areshown in FIG. 8;

FIG. 10 is a front perspective view of the image stabilizing mechanismand the radially-retracting mechanism, illustrating the retracted stateof a CCD holder in the retracted state of the zoom lens shown in FIG. 1;

FIG. 11 is a front perspective view of the image stabilizing mechanismand the radially-retracting mechanism, illustrating the optical-axisadvanced state of the CCD holder in a photographic state of the zoomlens;

FIG. 12 is a rear perspective view of a portion of the image stabilizingmechanism as viewed from the rear side of FIGS. 10 and 11;

FIG. 13 is a front elevational view of the image stabilizing mechanismand the radially-retracting mechanism in the state shown in FIG. 10, asviewed from the front in the optical axis direction;

FIG. 14 is a front elevational view of the image stabilizing mechanismand the radially-retracting mechanism in the state shown in FIG. 11, asviewed from the front in the optical axis direction;

FIG. 15 is a rear perspective view of the zoom lens in the retractedstate of the zoom lens shown in FIG. 1;

FIG. 16 is a front perspective view of a horizontal moving frame and avertical moving frame which support the CCD holder, and associatedelements;

FIG. 17 is a front view of the horizontal moving frame, the verticalmoving frame and the associated elements shown in FIG. 16;

FIG. 18 is a rear view of the horizontal moving frame, the verticalmoving frame and the associated elements shown in FIGS. 16 and 17;

FIG. 19 is a cross-sectional view of the CCD holder, the horizontalmoving frame, the vertical moving frame and other elements, taken alongD1-D1 line shown in FIG. 17;

FIG. 20 is a front elevational view of the elements shown in FIGS. 16through 17 and other associated elements, illustrating an imagestabilizing action in the horizontal direction by an operation of ahorizontal driving lever;

FIG. 21 is a front elevational view of the elements shown in FIG. 20,illustrating an image stabilizing action in the vertical direction by anoperation of a vertical driving lever;

FIG. 22 is a front elevational view of elements of the image stabilizingmechanism and the radially-retracting mechanism, illustrating theretracted state of the CCD holder, the horizontal moving frame and thevertical moving frame which are retracted by an operation of aretracting lever;

FIG. 23 is a front elevational view of the elements shown in FIG. 22,illustrating a state in which the CCD holder, the horizontal movingframe and the vertical moving frame return to their respectivephotographing positions where the CCD holder is positioned on thephotographing optical axis when the retracting lever is disengaged fromthe vertical moving frame to stop upholding the vertical moving frame;

FIG. 24 is a front elevational view of elements shown in FIG. 8 forillustrating the relationship between the horizontal driving lever andthe vertical motion of the CCD holder, the horizontal moving frame, andthe vertical moving frame;

FIG. 25 is an exploded perspective view of a second embodiment of thezoom lens to which the present invention is applied;

FIG. 26 is an exploded perspective view of elements of the imagestabilizing mechanism and the radially-retracting mechanism in thesecond embodiment of the zoom lens;

FIG. 27 is a front perspective view of the image stabilizing mechanismand the radially-retracting mechanism in the second embodiment of thezoom lens, illustrating the retracted state of a CCD holder in theradially retracted state of the zoom lens;

FIG. 28 is a front perspective view of the image stabilizing mechanismand the radially-retracting mechanism in the second embodiment of thezoom lens, illustrating the optical-axis advanced state of the CCDholder in a photographic state of the zoom lens;

FIG. 29 is a rear perspective view of a portion of an x-direction imagestabilizing mechanism as viewed from the rear side of FIGS. 27 and 28;

FIG. 30 is a front elevational view of the image stabilizing mechanismand the radially-retracting mechanism in the state shown in FIG. 27, asviewed from the front in the optical axis direction;

FIG. 31 is a front elevational view of the image stabilizing mechanismand the radially-retracting mechanism in the state shown in FIG. 28, asviewed from the front in the optical axis direction; and

FIG. 32 is a front perspective view of a horizontal moving frame and avertical moving frame which support the CCD holder, and associatedelements in the second embodiment of the zoom lens.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1 and 2 show cross-sections of a zoom lens 10 which isincorporated in a zoom lens camera. The zoom lens 10 is provided with abox-shaped housing 11 and a retractable barrel portion 12 retractablysupported inside the housing 11. The outside of the housing 11 iscovered by exterior components of the camera; the exterior componentsare not shown in the drawings. A photographing optical system of thezoom lens 10 includes a first lens group 13 a, a shutter 13 b, adiaphragm 13 c, a second lens group 13 d, a third lens group 13 e(rearmost lens group), a low-pass filter 13 f, and a CCD image sensor 13g (hereinafter referred to as CCD), in that order from the object side(the left side as viewed in FIGS. 1 and 2). As shown in FIG. 5, the CCD13 g is electrically connected to a control circuit 14 a having an imageprocessing circuit. Thus, an electronic image can be displayed on an LCDmonitor 14 b provided on an outer surface of the camera, and theelectronic image data can be recorded in a memory 14 c. In aphotographic state (ready-to-photograph state) of the zoom lens 10 shownin FIG. 2, all of the optical elements constituting the photographingoptical system are aligned on the same photographing optical axis Z1. Onthe other hand, in an accommodated (radially retracted) state of thezoom lens 10 shown in FIG. 1, the third lens group 13 e , the low-passfilter 13 f and the CCD 13 g are moved away from the photographingoptical axis Z1 to be radially retracted upward in the housing 11, andthe second lens group 13 d is linearly retracted into the space createdas a result of the upward radial retracting movement of the third lensgroup 13 e, the low-pass filter 13 f and the CCD 13 g, which reduces thelength of the zoom lens 10 in the retracted state thereof. The overallstructure of the zoom lens 10 that includes a radially-retractingmechanism for radially retracting optical elements upward will bedescribed hereinafter. In the following description, the verticaldirection and the horizontal direction of the zoom lens camera bodyequipped with the zoom lens 10 as viewed from the front thereof aredefined as a y-axis and an x-axis, respectively.

The housing 11 is provided with a hollow box-shaped portion 15 and ahollow fixed ring portion 16 which is formed on a front wall 15 a of thebox-shaped portion 15 so as to enclose the photographing optical systemabout the photographing optical axis Z1. A rotation center axis Z0serving as the center of the fixed ring portion 16 is parallel to thephotographing optical axis Z1 and eccentrically located below thephotographing optical axis Z1. A retraction space (accommodation space)SP (FIGS. 1 and 2) is formed inside the box-shaped portion 15 and abovethe fixed ring portion 16.

A zoom gear 17 (FIGS. 8, 10 and 11) is supported on an inner peripheralsurface side of the fixed ring portion 16 to be rotatable on an axis ofrotation parallel to the rotation center axis Z0. The zoom gear 17 isrotated forward and reverse by a zoom motor MZ (FIGS. 5, 10, and 11)supported by the housing 11. In addition, the fixed ring portion 16 isprovided on an inner peripheral surface thereof with a female helicoid16 a, a circumferential groove 16 b and a plurality of linear guidegrooves 16 c (only one of them is shown in FIG. 8). The circumferentialgroove 16 b is an annular groove with its center on the rotation centeraxis Z0, while the plurality of the linear guide grooves 16 c areparallel to the rotation center axis Z0 (see FIGS. 3, 4 and 8).

A helicoid ring 18 is supported inside the fixed ring portion 16 to berotatable about the rotation center axis Z0. The helicoid ring 18 isprovided with a male helicoid 18 a which is engaged with the femalehelicoid 16 a of the fixed ring portion 16 and thus can advance andretract in the optical axis direction while rotating due to theengagement of the female helicoid 16 a with the male helicoid 18 a. Thehelicoid ring 18 is further provided, on an outer peripheral surfacethereof in front of the female helicoid 18 a, with a plurality ofrotation guiding protrusions 18 b (only two of them are shown in FIG.8). In a state shown in FIGS. 2 through 4 in which the helicoid ring 18advances to the frontmost position thereof with respect to the fixedring portion 16, the female helicoid 16 a and the male helicoid 18 a aredisengaged from each other while the plurality of rotation guidingprotrusions 18 b are slidably fitted in the circumferential groove 16 bso that the helicoid ring 18 is prevented from further moving in theoptical axis direction and is allowed only to rotate at a fixed positionin the optical axis direction. The helicoid ring 18 is further providedon threads of the male helicoid 18 a with an annular spur gear 18 cwhich is in mesh with the zoom gear 17. Teeth of the spur gear 18 c arealigned parallel to the photographing optical axis Z1. The zoom gear 17is elongated in the axial direction thereof so as to remain engaged withthe spur gear 18 c at all times over the entire range of movement of thehelicoid ring 18 from a retracted state of the helicoid ring 18 shown inFIGS. 1 and 10 to an extended state of the helicoid ring 18 shown inFIGS. 2 and 11. The helicoid ring 18 is constructed by combining tworing members which are splittable in the optical axis direction. InFIGS. 10 and 11, only the rear ring member of the helicoid ring 18 isshown.

A linear guide ring 20 is supported inside the helicoid ring 18. Thelinear guide ring 20 is provided in the vicinity of the rear end thereofwith a linear guide projection 20 a, and is guided linearly along therotation center axis Z0 (and the photographing optical axis Z1) by theslidable engagement of the linear guide projection 20 a with the linearguide groove 16 c of the fixed ring portion 16 as shown in FIG. 4. Arotation guiding portion 21 is provided between the inner peripheralsurface of the helicoid ring 18 and the outer peripheral surface of thelinear guide ring 20. The helicoid ring 18 is supported by the linearguide ring 20 to be rotatable with respect to the linear guide ring 20and to be movable together with the linear guide ring 20 in the opticalaxis direction via the rotation guiding portion 21. The rotation guidingportion 21 consists of a plurality of circumferential grooves providedat different positions in the axial direction and radial protrusions,each of which is slidably engaged in the corresponding circumferentialgroove (see FIGS. 3 and 4).

The linear guide ring 20 is provided on an inner peripheral surfacethereof with a plurality of linear guide grooves 20 b (only one of themis shown in each of FIGS. 1 through 4) which extend parallel to therotation center axis Z0 (and the photographing optical axis Z1). Aplurality of linear guide projections 22 a (only one of them is shown ineach of FIGS. 1 through 4) which project radially outwards from a firstlens group linear guide ring 22 and a plurality of linear guideprojections 23 a(only one of them is shown in each of FIGS. 1 through 4)which project radially outwards from a second lens group linear guidering 23 are slidably engaged with the plurality of linear guide grooves20 b, respectively. The first lens group linear guide ring 22 guides afirst lens group support frame 24 linearly in a direction parallel tothe rotation center axis Z0 (and the photographing optical axis Z1) viaa plurality of linear guide grooves 22 b (only one of them is shown ineach of FIGS. 2 and 3) formed on an inner peripheral surface of thefirst lens group linear guide ring 22. The second lens group linearguide ring 23 guides a second lens group support frame 25 linearly in adirection parallel to the rotation center axis Z0 (and the photographingoptical axis Z1) via a plurality of linear guide keys 23 b (only one ofthem is shown in each of FIGS. 1 through 4). The first lens groupsupport frame 24 supports the first lens group 13 a via a focusing frame29, and the second lens group support frame 25 supports the second lensgroup 13 d.

A cam ring 26 is provided inside the linear guide ring 20 to berotatable about the rotation center axis Z0. The cam ring 26 issupported by the first lens group linear guide ring 22 and the secondlens group linear guide ring 23 to be rotatable with respect to each ofthe first lens group linear guide ring 22 and the second lens grouplinear guide ring 23 and to movable in the optical axis directiontogether therewith via rotation guiding portions 27 and 28 (see FIG. 4).As shown in FIGS. 3 and 4, the rotation guiding portion 27 is composedof a discontinuous circumferential groove 27 a (not shown in FIG. 3)which is formed on an outer peripheral surface of the cam ring 26, andan inner flange 27 b which projects radially inwards from the first lensgroup linear guide ring 22 to be slidably engaged in the discontinuouscircumferential groove 27 a. As shown in FIGS. 3 and 4, the rotationguiding portion 28 is composed of a discontinuous circumferential groove28 a (not shown in FIG. 3) formed on an inner peripheral surface of thecam ring 26 and an outer flange 28 b which projects radially outwardsfrom the second lens group linear guide ring 23 to be slidably engagedin the discontinuous circumferential groove 28 a.

As shown in FIG. 4, the cam ring 26 is provided thereon with a pluralityof follower protrusions 26 a (only one of them is shown in FIG. 4) whichproject radially outwards. The plurality of follower protrusions 26 apasses through a plurality of follower guide slots 20 c (only one ofthem is shown in FIG. 4) formed in the linear guide ring 20 to beengaged in a plurality of rotation transfer grooves 18 d (only one ofthem is shown in FIG. 4) formed on an inner peripheral surface of thehelicoid ring 18. Each rotation transfer groove 18 d is parallel to therotation center axis Z0 (and the photographing optical axis Z1), andeach follower protrusion 26 a is slidably engaged in the associatedrotation transfer groove 18 d to be prevented from moving in thecircumferential direction relative to the associated rotation transfergroove 18 d. Accordingly, the rotation of the helicoid ring 18 istransferred to the cam ring 26 via the engagement between the pluralityof rotation transfer grooves 18 d and the plurality of followerprotrusions 26 a. Although the development shape of each follower guidegroove 20 c is not shown in the drawings, each follower guide groove 20c is a guide groove including a circumferential groove portion with itscenter on the rotation center axis Z0 and an inclined lead grooveportion parallel to the female helicoid 16 a. Accordingly, when rotatedby a rotation of the helicoid ring 18, the cam ring 26 rotates whilemoving forward or rearward along the rotation center axis Z0 (and thephotographing optical axis Z1) if each follower protrusion 26 a isengaged in the lead groove portion of the associated follower guidegroove 20 c, and rotates at a fixed position in the optical axisdirection without moving forward or rearward if each follower protrusion26 a is engaged in the circumferential groove portion of the associatedfollower guide groove 20 c.

The cam ring 26 is a double-sided cam ring having a plurality of outercam grooves 26 b (only one of them is shown in FIG. 3) and a pluralityof inner cam grooves 26 c (only one of them is shown in each of FIGS. 3and 4) on outer and inner peripheral surfaces of the cam ring 26,respectively. The plurality of outer cam grooves 26 b are slidablyengaged with a plurality of cam followers 24 a (only one of them isshown in FIG. 3) which project radially inwards from the first lensgroup support frame 24, respectively, while the plurality of inner camgrooves 26 c are slidably engaged with a plurality of cam followers 25 a(only one of them is shown in each of FIGS. 3 and 4) which projectradially outwards from the second lens group support frame 25.Accordingly, when the cam ring 26 is rotated, the first lens groupsupport frame 24 that is guided linearly in the optical axis directionby the first lens group linear guide ring 22 moves forward and rearwardalong the rotation center axis Z0 (and the photographing optical axisZ1) in predetermined motion in accordance with contours of the pluralityof outer cam grooves 26 b. Likewise, when the cam ring 26 is rotated,the second lens group support frame 25 that is guided linearly in theoptical axis direction by the second lens group linear guide ring 23moves forward and rearward along the rotation center axis Z0 (and thephotographing optical axis Z1) in predetermined motion in accordancewith contours of the plurality of the plurality of inner cam grooves 26c.

The second lens group support frame 25 is provided with a cylindricalportion 25 b (see FIGS. 1 and 2) which holds the second lens group 13 d,and supports the shutter 13 b and the diaphragm 13 c in front of thecylindrical portion 25 b to allow each of the shutter 13 b and thediaphragm 13 c to be opened and closed. The shutter 13 b and thediaphragm 13 c can be opened and closed by a shutter actuator MS and adiaphragm actuator MA, respectively, which are supported by the secondlens group support frame 25 (see FIGS. 5 and 15).

The focusing frame 29 which holds the first lens group 13 a is supportedby the first lens group support frame 24 to be movable along therotation center axis Z0 (and the photographing optical axis Z1). Thefocusing frame 29 can be moved forward and rearward by a focusing motorMF (see FIG. 5).

The operation of each of the zoom motor MZ, the shutter actuator MS, thediaphragm actuator MA and the focusing motor MF is controlled by thecontrol circuit 14 a. Upon turning on a main switch 14 d (see FIG. 5) ofthe camera, the zoom motor MZ is driven to bring the zoom lens 10 to thephotographic state shown in FIG. 2. Upon turning off the main switch 14d, the zoom lens 10 is moved from the photographic state to theretracted state shown in FIG. 1.

The above described operation of the zoom lens 10 is summarized asfollows. Upon turning on the main switch 14 d in the retracted state ofthe zoom lens 10 shown in FIG. 1, the zoom gear 17 is driven to rotatein a lens barrel advancing direction. Accordingly, the helicoid ring 18moves forward in the optical axis direction while rotating, andsimultaneously, the linear guide ring 20 linearly moves forward in theoptical axis direction together with the helicoid ring 18. In addition,the rotation of the helicoid ring 18 causes the cam ring 26 to moveforward in the optical axis direction while rotating relative to thelinear guide ring 20. The first lens group linear guide ring 22 and thesecond lens group linear guide ring 23 linearly move forward in theoptical axis direction together with the cam ring 26. Each of the firstlens group support frame 24 and the second lens group support frame 25moves in the optical axis direction relative to the cam ring 26 inpredetermined motion. Therefore, the moving amount of the first lensgroup 13 a in the optical axis direction when the zoom lens 10 isextended from the retracted state thereof is determined by adding themoving amount of the cam ring 26 relative to the fixed ring portion 16to the moving amount of the first lens group support frame 24 relativeto the cam ring 26 (the advancing/retracting amount of the first lensgroup support frame 24 by the cam groove 26 b). Furthermore, the movingamount of the second lens group 13 d in the optical axis direction whenthe zoom lens 10 is extended from the retracted state thereof isdetermined by adding the moving amount of the cam ring 26 relative tothe fixed ring portion 16 to the moving amount of the second lens groupsupport frame 25 relative to the cam ring 26 (the advancing/retractingamount of the second lens group support frame 25 by the cam groove 26c).

FIG. 6 shows the moving paths of the helicoid ring 18 and the cam ring26 and the moving paths of the first lens group 13 a and the second lensgroup 13 d relative to the cam ring 26 (the cam diagrams of the camgrooves 26 b and 26 c). The vertical axis represents the amount ofrotation (angular position) of the lens barrel from the retracted stateof the zoom lens 10 to the telephoto extremity thereof, and thehorizontal axis represents the amount of movement of the lens barrel inthe optical axis direction. As shown in FIG. 6, the helicoid ring 18 ismoved forward in the optical axis direction while rotating up to anangular position θ1 which is located at about the midpoint in the rangeof extension of the zoom lens 10 from the retracted position (shown inFIG. 1) to the wide-angle extremity (shown by the upper half of the zoomlens 10 from the photographing optical axis Z1 and shown in FIG. 2),whereas the helicoid ring 18 rotates at a fixed position in the opticalaxis direction as described above in the range of extension of the zoomlens 10 from the angular position θ1 to the telephoto extremity (shownby the lower half of the zoom lens 10 from the photographing opticalaxis Z1 and shown in FIG. 4). On the other hand, the cam ring 26 ismoved forward in the optical axis direction while rotating up to anangular position θ2 which is located immediately behind the wide-angleextremity of the zoom lens 10 in the range of extension of the zoom lens10 from the retracted position to the wide-angle extremity, whereas thecam ring 26 rotates at a fixed position in the optical axis direction asdescribed above in the range of extension of the zoom lens 10 from theangular position θ2 to the telephoto extremity, similar to the helicoidring 18. In the zooming range from the wide-angle extremity to thetelephoto-extremity, the moving amount of the first lens group 13 a inthe optical axis direction is determined from the moving amount of thefirst lens group support frame 24 relative to the cam ring 26 whichrotates at a fixed position in the optical axis direction (theadvancing/retracting amount of the first lens group support frame 24 viathe cam groove 26 b), while the moving amount of the second lens group13 d in the optical axis direction is determined from the moving amountof the second lens group support frame 25 relative to the cam ring 26which rotates at a fixed position in the optical axis direction (theadvancing/retracting amount of the second lens group support frame 25via the cam groove 26 c). The focal length of the zoom lens 10 is variedby the relative movement in the optical axis direction between the firstlens group 13 a and the second lens group 13 d. FIG. 7 shows the actualmoving path of the first lens group 13 a which is obtained by combiningthe moving amounts of the helicoid ring 18 and the cam ring 26 with themoving amount of the first lens group 13 a by the cam groove 26 b, andthe actual moving path of the second lens group 13 d which is obtainedby combining the moving amounts of the helicoid ring 18 and the cam ring26 with the moving amount by the cam groove 26 c.

In the zooming range from the wide-angle extremity to the telephotoextremity, a focusing operation is performed by moving the first lensgroup 13 a in the optical axis direction independently of other opticalelements by the focusing motor MF.

The operations of the first lens group 13 a and the second lens group 13d have been described above. In the zoom lens 10 of the presentembodiment, the optical elements of the zoom lens 10 from the third lensgroup 13 e to the CCD 13 g are retractable away from the photographingposition on the photographing optical axis Z1 to an off-optical-axisretracted position (radially retracted position) Z2 located above thephotographing position as described above. In addition, by moving theoptical elements from the third lens group 13 e to the CCD 13 g on aplane perpendicular to the photographing optical axis Z1, image shakecan also be counteracted. The retracting mechanism and the imagestabilizing mechanism will be discussed hereinafter.

As shown in FIGS. 8 and 19, the third lens group 13 e, the low-passfilter 13 f and the CCD 13 g are held by a CCD holder (common holder) 30to be provided as a unit. The CCD holder 30 is provided with a holderbody 30 a, a sealing member 30 b and a pressure plate 30 c. The thirdlens group 13 e is held by the holder body 30 a at a front end aperturethereof. The low-pass filter 13 f is held between a flange formed on aninner surface of the holder body 30 a and the sealing member 30 b, andthe CCD 13 g is held between the sealing member 30 b and the pressureplate 30 c. The holder body 30 a and the pressure plate 30 c are fixedto each other by three fixing screws 30 d (see FIGS. 15 and 18)separately arranged around the central axis of the CCD holder 30 (thephotographing optical axis Z1 in a photographic state of the zoom lens10). The three fixing screws 30 d also secure one end portion of animage transmission flexible PWB 31 to the rear surface of the pressureplate 30 c so that a supporting substrate of the CCD 13 g iselectrically connected to the image transmission flexible PWB 31.

The image transmission flexible PWB 31 extends from its connection endat the CCD 13 g to the retraction space SP in the housing 11. The imagetransmission flexible PWB 31 is provided with a first linear portion 31a, a U-shaped portion 31 b, a second linear portion 31 c, and a thirdlinear portion 31 d (see FIGS. 1 and 2). The first linear portion 31 ais substantially orthogonal to the photographing optical axis Z1 andextends upward. The U-shaped portion 31 b is bent forward from the firstlinear portion 31 a. The second linear portion 31 c extends downwardfrom the U-shaped portion 31 b. The third linear portion 31 d is foldedupward from the second linear portion 31 c. The third linear portion 31d is fixed to an inner surface of the front wall 15 a of the housing 11therealong. The first linear portion 31 a, the U-shaped portion 31 b andthe second linear portion 31 c (except the third linear portion 31 d)serve as a free-deformable portion which is freely resilientlydeformable according to the motion of the CCD holder 30.

The CCD holder 30 is supported by a horizontal moving frame (firstmoving frame) 32 via three adjusting screws 33 (see FIGS. 15 and 18)separately arranged around the central axis of the CCD holder 30 (thephotographing optical axis Z1 in a ready-photograph state of the zoomlens 10). Three compression coil springs 34 are installed between theCCD holder 30 and the horizontal moving frame 32. The shaft portions ofthe three adjusting screws 33 are inserted into the three compressioncoil springs 34, respectively. When the tightening amounts of theadjusting screws 33 are changed, the respective compression amounts ofthe coil springs 34 are changed. The adjusting screws 33 and thecompression coil springs 34 are provided at three different positionsaround the optical axis of the third lens group 13 e, and accordingly,the inclination of the CCD holder 30 with respect to the horizontalmoving frame 32, or the inclination of the optical axis of the thirdlens group 13 e with respect to the photographing optical axis Z1, canbe adjusted by changing the tightening amounts of the three adjustingscrews 33.

As shown in FIG. 16, the horizontal moving frame 32 is supported by avertical moving frame (second moving frame) 36 to be movable withrespect thereto via a horizontal guide shaft 35 extending in the x-axisdirection. Specifically, the horizontal moving frame 32 is provided witha rectangular frame portion 32 a which encloses the CCD holder 30 and anarm portion 32 b which extends horizontally from the frame portion 32 a.A spring supporting protrusion 32 c is formed on an upper surface of theframe portion 32 a, and an inclined surface 32 d and a positionrestricting surface 32 e are formed on an end portion of the arm portion32 b. The position restricting surface 32 e is a flat surface parallelto the y-axis. On the other hand, the vertical moving frame 36 isprovided with a pair of motion restricting frames 36 a and 36 b, aspring supporting portion 36 c, an upper bearing portion 36 d, and alower bearing portion 36 e. The pair of motion restricting frames 36 aand 36 b are provided spaced apart in the x-axis direction. The springsupporting portion 36 c is located between the pair of the motionrestricting frames 36 a and 36 b. The upper bearing portion 36 d islocated on a line extended from the spring supporting portion 36 c inthe x-axis direction. The lower bearing portion 36 e is located belowthe upper bearing portion 36 d. As shown in FIG. 17, the horizontalmoving frame 32 is supported by the vertical moving frame 36 in a statewhere the frame portion 32 a is positioned in the space between the pairof motion restricting frames 36 a and 36 b and where the inclinedsurface 32 d and the position restricting surface 32 e of the armportion 32 b are positioned between the motion restricting frame 36 band the upper bearing portion 36 d.

One end of the horizontal guide shaft 35 is fixed to the motionrestricting frame 36 a of the vertical moving frame 36, and the otherend of the horizontal guide shaft 35 is fixed to the upper bearingportion 36 d of the vertical moving frame 36. Two through-holes arerespectively formed in the motion restricting frame 36 b and the springsupporting portion 36 c to be horizontally aligned to each other so asto allow the horizontal guide shaft 35 to pass through the motionrestricting frame 36 b and the spring supporting portion 36 c.Horizontal through-holes 32 x 1 and 32 x 2 (see FIG. 17) into which thehorizontal guide shaft 35 is inserted are formed in the arm portion 32 band the spring supporting protrusion 32 c of the horizontal moving frame32, respectively. The horizontal through-holes 32 x 1 and 32 x 2 of thehorizontal moving frame 32 and the aforementioned two through-holeswhich are respectively formed in the motion restricting frame 36 b andthe spring supporting portion 36 c are horizontally aligned with eachother. Since the horizontal guide shaft 35 is slidably fitted in thehorizontal through-holes 32 x 1 and 32 x 2, the horizontal moving frame32 is supported by the vertical moving frame 36 to be movable withrespect to the vertical moving frame 36 in the x-axis direction. Ahorizontal moving frame biasing spring 37 is installed on the horizontalguide shaft 35 between the spring supporting protrusion 32 c and thespring supporting portion 36 c. The horizontal moving frame biasingspring 37 is a compression coil spring and biases the horizontal movingframe 32 in a direction (leftward as viewed in FIG. 17) to make thespring supporting protrusion 32 c approach the motion restricting frame36 a.

Vertical through-holes 36 y 1 and 36 y 2 (see FIG. 16) are furtherformed in the upper bearing portion 36 d and the lower bearing portion36 e of the vertical moving frame 36, respectively, which extend in aline along the y-axis direction which is orthogonal to the photographingoptical axis Z1. The vertical through-hole 36 y 1 and the verticalthrough-hole 36 y 2 are vertically aligned, and a vertical guide shaft38 (see FIGS. 8 and 9) passes through vertical through-hole 36 y 1 andthe vertical through-hole 36 y 2. Both ends of the vertical guide shaft38 are fixed to the housing 11, and therefore, the vertical moving frame36 can move along the vertical guide shaft 38 in the y-axis directioninside the camera. More specifically, the vertical moving frame 36 canmove between the photographing position shown in FIG. 1 and theretracted position shown in FIG. 2. When the vertical moving frame 36 ispositioned in the photographing position as shown in FIG. 2, the centersof the third lens group 13 e, the low-pass filter 13 f and the CCD 13 gin the CCD holder 30 are positioned on the photographing optical axisZ1. When the vertical moving frame 36 is positioned in the radiallyretracted position as shown in FIG. 1, the centers of the third lensgroup 13 e, the low-pass filter 13 f and the CCD 13 g are positioned inthe off-optical-axis retracted position Z2 that is located above thefixed ring portion 16.

The vertical moving frame 36 is provided with a spring hooking portion36 f which projects horizontally from a side surface of the verticalmoving frame 36 in a direction away from the vertical through-hole 36 y1, and a vertical moving frame biasing spring 39 is extended between thespring hooking portion 36 f and a spring hooking portion 11 a (see FIGS.8 and 15) fixed to the housing 11 therein. The vertical moving framebiasing spring 39 is an extension coil spring and biases the verticalmoving frame 36 downward (i.e., toward the photographing positionthereof shown in FIG. 2).

As described above, the horizontal moving frame 32 that holds the CCDholder 30 is supported by the vertical moving frame 36 to be movable inthe x-axis direction with respect to the vertical moving frame 36, andthe vertical moving frame 36 is supported by the housing 11 via thevertical guide shaft 38 to be movable in the y-axis direction withrespect to the housing 11. Image shake can be counteracted by moving theCCD holder 30 in the x-axis direction and the y-axis direction. To thisend, a horizontal driving lever 40 and a vertical driving lever 41 areprovided as elements of a driving mechanism which achieves such movementof the CCD holder 30. The horizontal driving lever 40 and the verticaldriving lever 41 are pivoted on a lever pivot shaft 42 to be rotatable(swingable) independently of each other. The lever pivot shaft 42 ispositioned in the housing 11 and fixed thereto to be parallel to thephotographing optical axis Z1.

As shown in FIGS. 9 and 20, the horizontal driving lever 40 is pivotedat the lower end thereof on the lever pivot shaft 42, and is provided atthe upper end of the horizontal driving lever 40 with a force-applyingend 40 a. The horizontal driving lever 40 is provided in the vicinity ofthe force-applying end 40 awith an operation pin 40 b which projectsrearward in the optical axis direction and a spring hooking portion 40 cwhich projects forward in the optical axis direction. As shown in FIG.12, the force-applying end 40 a of the horizontal driving lever 40 abutsagainst a lug 43 bof a first moving member 43. The first moving member43 is supported by a pair of parallel guide bars 44 (44 a and 44 b) tobe slidable thereon in the x-axis direction, and a driven nut member 45abuts against the first moving member 43. The driven nut member 45 isprovided with a female screw hole 45 b and a rotation restricting groove45 a (see FIG. 9) which is slidably fitted on the guide bar 44 b. Adrive shaft (a feed screw) 46 a of a first stepping motor 46 is screwedinto the female screw hole 45 b. As shown in FIGS. 13 and 14, the drivennut member 45 abuts against the first moving member 43 from the leftside. One end of an extension coil spring 47 is hooked on the springhooking portion 40 c of the horizontal driving lever 40, and the otherend of the spring 47 is hooked on a spring hooking portion 11 b whichprojects from an inner surface of the housing 11 (see FIG. 12). Theextension coil spring 47 biases the horizontal driving lever 40 in adirection to bring the first moving member 43 to abut against the drivennut member 45, i.e., in a counterclockwise direction as viewed in FIGS.13, 14 and 20. Due to this structure, driving the first stepping motor46 causes the driven nut member 45 to move along the pair of guide bars44, and at the same time causes the first moving member 43 to movetogether with the driven nut member 45, thus causing the horizontaldriving lever 40 to swing about the lever pivot shaft 42. Specifically,moving the driven nut member 45 rightward as viewed in FIGS. 13 and 14causes the driven nut member 45 to press the first moving member 43 inthe same direction against the biasing force of the extension spring 47,thus causing the horizontal driving lever 40 to rotate clockwise asviewed in FIGS. 13 and 14. Conversely, moving the driven nut member 45leftward as viewed in FIGS. 13 and 14 causes the first moving member 43to move in the same direction while following the leftward movement ofthe driven nut member 45 due to the biasing force of the extension coilspring 47, thus causing the horizontal driving lever 40 to rotatecounterclockwise as viewed in FIGS. 13 and 14.

As shown in FIG. 20, the operation pin 40 b of the horizontal drivinglever 40 abuts against the position restricting surface 32 e that isprovided on the end portion of the arm portion 32 b of the horizontalmoving frame 32. Since the horizontal moving frame 32 is biased leftwardas viewed in FIG. 20 by the horizontal moving frame biasing spring 37,the operation pin 40 b remains in contact with the position restrictingsurface 32 e. When the horizontal driving lever 40 swings, the positionof the operation pin 40 b changes along the x-axis direction, so thatthe horizontal moving frame 32 moves along the horizontal guide shaft35. Specifically, rotating the horizontal driving lever 40 clockwise asviewed in FIG. 20 causes the operation pin 40 b to press the positionrestricting surface 32 e, which causes the horizontal moving frame 32 tomove rightward as viewed in FIG. 20 against the biasing force of thehorizontal moving frame biasing spring 37. Conversely, rotating thehorizontal driving lever 40 counterclockwise as viewed in FIG. 20 causesthe operation pin 40 b to move in a direction away from the positionrestricting surface 32 e (leftward as viewed in FIG. 20), which causesthe horizontal moving frame 32 to move in the same direction whilefollowing the leftward movement of the operation pin 40 b due to thebiasing force of the horizontal moving frame biasing spring 37.

As shown in FIGS. 9 and 21, the vertical driving lever 41 is pivoted atits lower end on the lever pivot shaft 42, as in the case of thehorizontal driving lever 40, and is provided at the upper end of thevertical driving lever 41 with a force-applying end 41 a. The verticaldriving lever 41 is longer than the horizontal driving lever 40, and theforce-applying end 41 a protrudes upward to a position higher than theposition of the force-applying end 40 a. The vertical driving lever 41is provided between the lever rotating shaft 42 and the force-applyingend 41 a with a pressing inclined surface 41 b which projects rightwardas viewed in FIG. 21. The vertical driving lever 41 is provided abovethe pressing inclined surface 41 b with a spring hooking portion 41 c.As shown in FIG. 12, the force-applying end 41 a abuts against a lug 50b of a second moving member 50. The second moving member 50 is supportedby a pair of parallel guide bars 51 (51 a and 51 b) to be slidablethereon in the x-axis direction, and a driven nut member 52 abutsagainst the second moving member 50. The driven nut member 52 isprovided with a female screw hole 52 b and a rotation restricting groove52 a which is slidably fitted on the guide bar 51 b. A drive shaft (afeed screw) 53 a of a second stepping motor 53 is screwed into thefemale screw hole 52 b. As shown in FIGS. 13 and 14, the driven nutmember 52 abuts against the second moving member 50 from the left sideas viewed from the front of the camera. One end of an extension coilspring 54 is hooked on the spring hooking portion 41 c of the verticaldriving lever 41, and the other end of the spring 54 is hooked on aspring hooking portion (not shown) formed on an inner surface of thehousing 11. The extension coil spring 54 biases the vertical drivinglever 41 in a direction to bring the second moving member 50 to abutagainst the driven nut member 52, i.e., in the counterclockwisedirection as viewed in FIGS. 13, 14, and 21. Due to this structure,driving the second stepping motor 53 causes the driven nut member 52 tomove along the pair of guide bars 51, and at the same time causes thesecond moving member 50 to move together with the driven nut member 52,thus causing the vertical driving lever 41 to swing about the leverpivot shaft 42. Specifically, moving the driven nut member 52 rightwardas viewed in FIGS. 13 and 14 causes the driven nut member 52 to pressthe second moving member 50 in the same direction against the biasingforce of the extension spring 54, thus causing the vertical drivinglever 41 to rotate clockwise as viewed in FIGS. 13 and 14. Conversely,moving the driven nut member 52 leftward as viewed in FIGS. 13 and 14causes the second moving member 50 to move in the same direction whilefollowing the leftward movement of the driven nut member 52 due to thebiasing force of the extension spring 54, thus causing the verticaldriving lever 41 to rotate counterclockwise as viewed in FIGS. 13 and14.

As shown in FIG. 21, the pressing inclined surface 41 b of the verticaldriving lever 41 can come into contact with a pressed pin 36 g whichprojects forward from the upper bearing portion 36 d of the verticalmoving frame 36. Since the vertical moving frame 36 is biased downwardsas viewed in FIG. 21 by the vertical moving frame biasing spring 39, thepressed pin 36 g always remains in contact with the pressing inclinedsurface 41 b. When the vertical driving lever 41 swings, the abuttingangle of the pressing inclined surface 41 b relative to the pressed pin36 g changes, so that the vertical moving frame 36 moves along thevertical guide shaft 38. Specifically, rotating the vertical drivinglever 41 clockwise as viewed in FIG. 21 causes the pressing inclinedsurface 41 b to press the pressed pin 36 g upward as viewed in FIG. 21,which causes the vertical moving frame 36 to move upward against thebiasing force of the vertical moving frame biasing spring 39.Conversely, rotating the vertical driving lever 41 counterclockwise asviewed in FIG. 21 causes the abutting point on the pressing inclinedsurface 41 b relative to the pressed pin 36 g to descend, which causesthe vertical moving frame 36 to move downward by the biasing force ofthe vertical moving frame biasing spring 39.

In the above-described structure, the horizontal moving frame 32 can becaused to move left or right in the x-axis direction by driving thefirst stepping motor 46 forward or reverse. Furthermore, the verticalmoving frame 36 can be caused to move upwards or downwards in the y-axisdirection by driving the second stepping motor 53 forward or reverse.

The first moving member 43 is provided with a plate portion 43 a, andthe second moving member 50 is provided with a plate portion 50 a. Theinitial position of the horizontal moving frame 32 can be detected by aphoto sensor 55 having a light emitter and a light receiver which arespaced apart from each other as shown in FIGS. 8, 10 and 11 when theplate portion 43 a passes between the light emitter and the lightreceiver of the photo sensor 55. The plate portion 43 a and the photosensor 55 constitute a photo interrupter. Likewise, the initial positionof vertical moving frame 36 can be detected by a photo sensor 56 havinga light emitter and a light receiver which are spaced apart from eachother as shown in FIGS. 8, 10 and 11 when the plate portion 50 a passesbetween the light emitter and the light receiver of the photo sensor 56.The plate portion 50 a and the photo sensor 56 constitute a photointerrupter. The two photo sensors 55 and 56 are fixed in two fixingholes 15 a 1 and 15 a 2 (see FIG. 8) formed on a front wall of thehousing 11 to be supported thereby.

The present embodiment of the zoom lens camera has an image-shakedetection sensor (detector) 57 (see FIG. 5) which detects the angularvelocity around two axes (the vertical and horizontal axes of thecamera) orthogonal to each other in a plane perpendicular to thephotographing optical axis Z1. The magnitude and the direction of camerashake (vibrations) are detected by the image-shake detection sensor 57.The control circuit 14 a determines a moving angle by time-integratingthe angular velocity of the camera shake in the two axial directions,detected by the image-shake detection sensor 57. Subsequently, thecontrol circuit 14 a calculates from the moving angle the moving amountsof the image on a focal plane (imaging surface/light receiving surfaceof the CCD 13 g) in the x-axis direction and in the y-axis direction.The control circuit 14 further calculates the driving amounts and thedriving directions of the horizontal moving frame 32 and the verticalmoving frame 36 for the respective axial directions (driving pulses forthe first stepping motor 46 and the second stepping motor 53) in orderto counteract the camera shake. Thereupon, the first stepping motor 46and the second stepping motor 53 are actuated and the operations thereofare controlled in accordance with the calculated values. In this manner,each of the horizontal moving frame 32 and the vertical moving frame 36is driven in the calculated direction by the calculated amount in orderto counteract the shake of the photographing optical axis Z1 to therebystabilize the image on the focal plane. The camera can be put into thisimage stabilization mode by turning on a photographing mode selectswitch 14 e (see FIG. 5). If the switch 14 e is in an off-state, theimage stabilizing capability is deactivated so that a normalphotographing operation is performed.

The present embodiment of the zoom lens camera uses part of theabove-described image stabilizing mechanism to perform the retractingoperation (radially retracting operation) of the third lens group 13 e,the low-pass filter 13 f and the CCD 13 g toward the off-optical-axisretracted position Z2 into the retraction space SP when the zoom lens 10is retracted from a photographic state. As shown in FIGS. 22 and 23, aretracting lever 60 is provided below the vertical moving frame 36. Theretracting lever 60 is pivoted on a pivot shaft 60 a to be rotatable(swingable) thereabout. A coaxial gear 61 is installed adjacent to theretracting lever 60, and is coaxially provided on the pivot shaft 60 ato be rotatable on the pivot shaft 60 a. A rotational force istransferred from an interconnecting gear 64 to the coaxial gear 61 viatwo relay gears 62 and 63. The pivot shaft 60 a, which serves as therotation axis of each of the retracting lever 60 and the coaxial gear61, the rotation axes of the relay gears 62 and 63, and the rotationaxis of the interconnecting gear 64 are each parallel to the rotationcenter axis Z0 (and the photographing optical axis Z1).

As shown in FIGS. 9, 22 and 23, the retracting lever 60 is provided inthe vicinity of the pivot shaft 60 a with a rotation transfer protrusion60 b having a sector-shaped cross section and projecting forward in theoptical axis direction. The coaxial gear 61 is provided, at a rear endthereof, with a rotation transfer protrusion 61 a which projectsrearward in the optical axis direction, has the same diameter of that ofthe rotation transfer protrusion 60 b, and is coaxial with the pivotshaft 60 a. Namely, the rotation transfer protrusion 60 b and therotation transfer protrusion 61 a have the same diameter and arepositioned on the pivot shaft 60 a to be circumferentially engageablewith each other. The coaxial gear 61 transfers a rotation thereof to theretracting lever 60 by engaging the rotation transfer protrusion 61 awith the rotation transfer protrusion 60 b of the retracting lever 60.When the coaxial gear 61 rotates in a direction to disengage therotation transfer protrusion 61 a from the rotation transfer protrusion60 b, the rotational force of the coaxial gear 61 is not transferred tothe retracting lever 60. The retracting lever 60 is biased to rotatecounterclockwise as viewed in FIGS. 22 and 23 by a torsion spring 60 c,and the housing 11 is provided therein with a stop projection 65 (seeFIGS. 13, 14, 22 and 23) which defines the limit of rotation of theretracting lever 60 in the biasing direction of the torsion spring 60 c.Namely, the retracting lever 60 comes in contact with the stopprojection 65 as shown in FIG. 23 when fully rotated counterclockwise asviewed in FIGS. 22 and 23.

The vertical moving frame 36 is provided on a bottom surface thereofwith an abutment surface 66 consisting of an arc-shaped surface 66 a anda leading surface 66 b. The arc-shaped surface 66 a has an arc shapewhich corresponds to an arc pivoted on the axis of the pivot shaft 60 aof the retracting lever 60, and the leading surface 66 b is formed as aflat inclined surface. The lowermost point of the leading surface 66 bis located at the portion thereof which is connected to the arc-shapedsurface 66 a, and the leading surface 66 b gradually rises in adirection away from the arc-shaped surface 66 a (in a direction toapproach the left side surface of the vertical moving frame 36 as viewedin FIGS. 22 and 23).

The interconnecting gear 64 is provided with a gear portion 64 a and arotation restricting portion 64 b at different positions in the axialdirection of interconnecting gear 64. The rotation restricting portion64 b has a non-circular (D-shaped) cross-sectional shape and includes alarge-diameter cylindrical portion 64 b 1 and a flat portion 64 b 2. Thelarge-diameter cylindrical portion 64 b 1 has an incomplete cylindricalshape having a diameter larger than that of the gear portion 64 a. Theflat portion 64 b 2 is formed on the rotation restricting portion 64 bin a manner so that a part of the large diameter cylindrical portion 64b 1 appears to be cut off to form a nearly flat shape. In an area inwhich the flat portion 64 b 2 is formed, the tips of the teeth of thegear portion 64 a project radially outwards from the rotationrestricting portion 64 b. The flat portion 64 b 2 is formed as a flatsurface which includes a straight line parallel to the axis of rotationof the interconnecting gear 64.

The interconnecting gear 64 is positioned to face the outer surface ofthe helicoid ring 18. The spur gear 18 c faces either the gear portion64 a of the interconnecting gear 64 (in the state shown in FIGS. 11 and14) or the rotation restricting portion 64 b (in the state shown FIGS.10 and 13) depending on the axial position (and the type of motion) ofthe helicoid ring 18 in the optical axis direction. When the helicoidring 18 rotates at a fixed position as described above, the spur gear 18c is engaged with the gear portion 64 a. As the helicoid ring 18 movesin the retracting direction from the fixed-position rotating state, thespur gear 18 c is disengaged from the interconnecting gear 64 to facethe rotation restricting portion 64 b, so that the transfer of rotationof the helicoid ring 18 to the interconnecting gear 64 is stopped.

The operation of the retracting lever 60 will be discussed in detailhereinafter. FIG. 23 shows elements of the image stabilizing mechanismand the retracting mechanism in a state where the zoom lens 10 is set atthe wide-angle extremity. In this state, the third lens group 13 e, thelow-pass filter 13 f and the CCD 13 g are positioned on thephotographing optical axis Z1 (see the upper half of the zoom lens 10shown in FIG. 2), and also the helicoid ring 18 is in a state where thehelicoid ring 18 is only allowed to rotate at a fixed position in theoptical axis direction (see FIG. 6) while the gear portion 64 a of theinterconnecting gear 64 is engaged with the spur gear 18 c of thehelicoid ring 18. When the helicoid ring 18 rotates in the retractingdirection from the wide-angle extremity, the coaxial gear 61 rotatesclockwise as viewed in FIG. 23 via the interconnecting gear 64 and therelay gears 62 and 63. As shown in FIG. 23, since the rotation transferprotrusion 61 a and the rotation transfer protrusion 60 b are slightlyapart from each other when the zoom lens 10 is set at the wide-angleextremity, no rotational force is transferred from the coaxial gear 61to the retracting lever 60 for a short period of time after the coaxialgear 61 starts rotating. Accordingly, the retracting lever 60 is held inthe position shown in FIG. 23 where the retracting lever 60 is incontact with the stop projection 65 due to the biasing force of thetorsion spring 60 c. Thereafter, upon the rotation transfer protrusion61 a coming into contact with the rotation transfer protrusion 60 b andpressing the rotation transfer protrusion 60 b, the retracting lever 60starts rotating clockwise with respect to FIG. 23 against the biasingforce of the torsion spring 60 c. In the present embodiment, the timingof the commencement of rotation of the retracting lever 60 substantiallycorresponds to the angular position θ2 at which the cam ring 26 startsretracting in the optical axis direction from the fixed positionrotation state (see FIG. 6).

When the retracting lever 60 rotates clockwise from the angular positionshown in FIG. 23, a force-applying end 60 d formed at the free end ofthe retracting lever 60 is brought into contact with the leading surface66 b of the abutment surface 66 of the vertical moving frame 36. Afurther clockwise rotation of the retracting lever 60 causes theretracting lever 60 to lift the vertical moving frame 36 according tothe inclined shape of the leading surface 66 b, thus causing thevertical moving frame 36 to move upward in the housing 11 along thevertical guide shaft 38.

On and after the angular position exceeding θ1 shown in FIG. 6, when thehelicoid ring 18 rotates in the retracting direction, the rotatingoperation of the helicoid ring 18 at a fixed position in the opticalaxis direction ends, and subsequently the helicoid ring 18 starts movingrearward in the optical axis direction while rotating. Thereupon, thespur gear 18 c of the helicoid ring 18 is disengaged from the gearportion 64 a of the interconnecting gear 64, which in turn faces theflat portion 64 b 2 of the rotation restricting portion 64 b. Since eachof the spur gear 18 c and the gear portion 64 a has a predeterminedlength in the optical axis direction, the engagement between the spurgear 18 c and the gear portion 64 a is not released at once immediatelyafter the fixed-position rotating state of the helicoid ring 18 changesto the rotating and retracting state thereof at the angular position θ1,but is released at an angular position θ3 at which the helicoid ring 18further retracts in the retracting direction by a small amount ofmovement. Due to this disengagement of the spur gear 18 c from the gearportion 64 a, the rotational force of the helicoid ring 18 is no longertransferred to the interconnecting gear 64, so that the upwardrotational motion of the retracting lever 60 is terminated. FIGS. 15 and22 show shows the retracting lever 60 in a state in which the upwardrotational motion thereof has been terminated. As can be seen in FIG.22, the force-applying end 60 d of the retracting lever 60 is in contactwith the arc-shaped surface 66 a after passing the boundary between thearc-shaped surface 66 a and the leading surface 66 b. In this state, thevertical moving frame 36 lifted by the retracting lever 60 have beenmoved into the retraction space SP in the housing 11 as shown in FIG. 1.

The retracting operation of the zoom lens 10 is not completed at theangular position θ3 where the upward retracting motion of the verticalmoving frame 36 is completed; the helicoid ring 18 and the cam ring 26further move rearward in the optical axis direction while rotating.Thereafter, when the helicoid ring 18 and the cam ring 26 reach theirrespective retracted positions shown in FIG. 1, the cylindrical portion25 b of the second lens group support frame 25 that holds the secondlens group 13 d is retracted into the space in the housing 11 which isformerly occupied by the vertical moving frame 36 when the zoom lens 10is in a photographic state. In this manner, the thickness of thephotographing optical system in the optical axis direction can bereduced in the retracted state of the zoom lens 10, which makes itpossible to reduce the thickness of the zoom lens 10, which in turnmakes it possible to reduce the thickness of a camera incorporating thezoom lens 10.

In the above-described retracting operation of the zoom lens 10, afterthe zoom lens 10 retracts to the angular position θ3 where theengagement between the gear portion 64 a of the interconnecting gear 64and the spur gear 18 c of the helicoid ring 18 is released, the spurgear 18 c faces the flat portion 64 b 2 of the rotation restrictingportion 64 b. In this state where the spur gear 18 c faces the flatportion 64 b 2, the flat portion 64 b 2 is positioned in close vicinityof the tooth top (outermost periphery/addendum circle) of the spur gear18 c. Therefore, even if the interconnecting gear 64 tries to rotate,the flat portion 64 b 2 abuts against the outer periphery of the spurgear 18 c to prevent the interconnecting gear 64 from rotating (seeFIGS. 10 and 13). In this manner, the interconnecting gear 64 isprevented from rotating accidentally in the retracted state of the zoomlens 10, and thus the retracting lever 60 can be securely locked in theupper rotational position. In other words, in the retracted state shownin FIG. 22, although the retracting lever 60 is biased counterclockwiseas viewed in FIG. 22 by the torsion spring 60 c, the retracting lever 60is prevented from rotating counterclockwise by a gear train consistingof the coaxial gear 61, the pair of relay gears 62 and 63 and theinterconnecting gear 64. The abutting physical relationship between theflat portion 64 b 2 of the interconnecting gear 64 and the spur gear 18c serves as a rotation restricting device for restricting rotation ofthe retracting lever 60. Therefore, the retracting lever 60 can besecurely held in a halting state without any complicated lockingmechanism.

In a state in which the vertical moving frame 36 is radially retractedupward completely out of the linear retracting path of the first andsecond lens groups 13 a and 13 d, the force-applying end 60 d of theretracting lever 60 abuts against the arc-shaped surface 66 a which hasan arc-shaped surface having its center on the axis of the pivot shaft60 a of the retracting lever 60. Therefore, even if the angle of theretracting lever 60 is changed, the vertical position of the verticalmoving frame 36 is not changed and held constant so long as theforce-applying end 60 d abuts against the arc-shaped surface 66 a.

The operation of the retracting mechanism from the wide-angle extremityto the retracted position has been described above. On the other hand,in the zooming range from the wide-angle extremity to the telephotoextremity, the spur gear 18 c of the helicoid ring 18 rotating at afixed position remains engaged with the gear portion 64 a of theinterconnecting gear 64, and thus the interconnecting gear 64 is rotatedaccording to the rotation of the helicoid ring 18. However, rotating thehelicoid ring 18 from the wide-angle extremity state shown in FIG. 23toward the telephoto extremity causes the coaxial gear 61 to rotatecounterclockwise as viewed in FIG. 23, i.e., in a direction to move therotation transfer protrusion 61 a away from the rotation transferprotrusion 60 b. Therefore, in the zooming range from the wide-angleextremity to the telephoto extremity, no rotational force is transferredto the retracting lever 60, and the retracting lever 60 is held at theangular position shown in FIG. 23. In this manner, the range of rotationof the retracting lever 60 can be minimized, thereby preventing anincrease in size of the zoom lens barrel.

When the vertical moving frame 36 is retracted upward to theoff-optical-axis retracted position Z2 as shown in FIG. 24, the positionrestricting surface 32 e that is provided on the arm portion 32 b of thehorizontal moving frame 32 is disengaged from the operation pin 40 bthat is provided on the horizontal driving lever 40. This disengagementof the position restricting surface 32 e from the operation pin 40 bcauses the horizontal moving frame 32 to move leftward as viewed in FIG.24 by the biasing force of the horizontal moving frame biasing spring 37up to a point at which the frame portion 32 a of the horizontal movingframe 32 abuts against the motion restricting frame 36 a of the verticalmoving frame 36. From this state, upon the vertical moving frame 36being moved down to the photographing optical axis Z1, the inclinedsurface 32 d of the horizontal moving frame 32 comes in contact with theoperation pin 40 b as shown by two-dot chain lines in FIG. 24. Theinclined surface 32 d is inclined so as to guide the operation pin 40 bto the position restricting surface 32 e side according to the downwardmotion of the vertical moving frame 36. Therefore, upon the verticalmoving frame 36 being moved down to the photographing position, theoperation pin 40 b is again engaged with the position restrictingsurface 32 e as shown in FIG. 20 and the frame portion 32 a of thehorizontal moving frame 32 returns to the neutral position thereofbetween the motion restricting frame 36 a and the motion restrictingframe 36 b.

FIGS. 25 through 32 show a second embodiment of the zoom lens 10.Although the first embodiment of the zoom lens 10 is provided with thevertical driving lever 41 and the second stepping motor 53 as a drivingdevice for driving the vertical moving frame 36, and is provided withthe retracting lever 60 as another driving device for retraction, thesecond embodiment of the zoom lens 10 is provided with a second steppingmotor 70 which is also used to serve as these driving devices.Therefore, the second embodiment of the zoom lens 10 is not providedwith elements corresponding to the vertical driving lever 41, the secondmoving member 50, the pair of guide bars 51, the driven nut member 52,the second stepping motor 53 and the extension coil spring 54 (see FIG.29). In FIGS. 25 through 32, elements and portions which are similar tothose in the first embodiment of the zoom lens are designated with thesame reference numerals, and the detailed description of such elementsare omitted in the following description.

As shown in FIGS. 27, 28, 30 and 31, the second stepping motor 70 isinstalled in the vicinity of the vertical guide shaft 38, and isprovided with a drive shaft (feed screw) 70 a which extends parallel tothe vertical guide shaft 38. A driven nut member 71 is screw-engagedwith the drive shaft 70 a. Specifically, as shown in FIG. 26, the drivennut member 71 is provided with a rotation restricting groove 71 a whichis slidably fitted on the vertical guide shaft 38, and a female screwhole 71 b which is screw-engaged with the drive shaft 70 a. Rotating thedrive shaft 70 a forward and reverse by driving the second steppingmotor 70 causes the driven nut member 71 to move upwards and downwardsin the y-axis direction along the vertical guide shaft 38. As shown inFIGS. 27, 28, 30 and 31, the driven nut member 71 is in contact with avertical moving frame (second moving frame) 136 (which corresponds tothe vertical moving frame 36 in the first embodiment of the zoom lens)from bottom thereof. Due to this structure, driving the second steppingmotor 70 causes the driven nut member 71 to move along the verticalguide shaft 38, thus causing the vertical moving frame 136 to move alongthe vertical guide shaft 38. Specifically, moving the driven nut member71 upward causes the driven nut member 71 to push a lower bearingportion 136 e of the vertical moving frame 136 upward, so that thevertical moving frame 136 moves upward against the biasing force of thevertical moving frame biasing spring 39. Conversely, moving the drivennut member 71 downward causes the vertical moving frame 136 to movedownward together with the driven nut member 71 by the biasing force ofthe vertical moving frame biasing spring 39.

The CCD holder 30 is supported by a horizontal moving frame (firstmoving frame) 132 which corresponds to the horizontal moving frame 32 ofthe first embodiment of the zoom lens. The horizontal moving frame 132is provided with a plate portion 32 f which is formed as a part of thearm portion 32 b to extend downward from the arm portion 32 b. The plateportion 32 f has a substantially inverted-L shape as viewed from thefront of the camera, and is elongated in the y-axis direction so thatthe lower end of the plate portion 32 f reaches down to the closevicinity of the lower bearing portion 136 e. Additionally, the verticalmoving frame 136 is provided at the end of the lower bearing portion 136e with a plate portion 36 s. As shown in FIGS. 27 and 28, two photosensors 155 and 156, each having a light emitter and a light receiverwhich are spaced apart from each other are installed in the housing 11.The initial position of the horizontal moving frame 132 can be detectedby the photo sensor 155 when the plate portion 32 f passes between thelight emitter and the light receiver of the photo sensor 155. The plateportion 32 f and the photo sensor 155 constitute a photo interrupter.Likewise, the initial position of the vertical moving frame 136 can bedetected by the photo sensor 156 when the plate portion 36 s passesbetween the light emitter and the light receiver of the photo sensor156. The plate portion 36 s and the photo sensor 156 constitute a photointerrupter.

The second stepping motor 70 moves the vertical moving frame 136 in they-axis direction within a predetermined range of movement (the range ofmovement for counteracting camera shake) in which the third lens group13 e, the low-pass filter 13 f and the CCD 13 g do not deviate from thephotographing optical axis Z1 in a photographic state of the zoom lens10 between the wide-angle extremity and the telephoto extremity. In thisphotographic state, the driven nut member 71 is located in the vicinityof the lower end of the drive shaft 70 a (see FIGS. 28 and 31).Thereafter, when the zoom lens 10 is retracted upon the main switch 14 dbeing turned off, the second stepping motor 70 moves the driven nutmember 71 upward to the close vicinity of the upper end of the driveshaft 70 a to retract the vertical moving frame 136 to theoff-optical-axis retracted position Z2 (see FIGS. 27 and 30). The driveshaft 70 a is made to serve as a feed screw extending parallel to thevertical guide shaft 38 to be capable of moving the vertical movingframe 136 from the photographing optical axis Z1 to the off-optical-axisretracted position (radially retracted position) Z2. The drive shaft 70a has an axial length longer than the distance between the photographingoptical axis Z1 and the off-optical-axis retracted position Z2 in they-axis direction.

The amount of retracting movement of the vertical moving frame 136 inthe y-axis direction can be determined by counting the driving pulses ofthe second stepping motor 70 from the initial position of the verticalmoving frame 136 that is detected by the photo interrupter that consistsof the plate portion 36 s and the photo sensor 156. The second steppingmotor 70 is stopped upon the number of driving pulses of the secondstepping motor 70 reaching a predetermined number of pulses. In thismanner, the vertical moving frame 136 is radially retracted into theretraction space SP (see FIGS. 1 and 2) in the housing 11. The timing ofthe commencement of the radially retracting operation of the verticalmoving frame 136 and the timing of the termination thereof can be freelyset. For instance, similar to the first embodiment of the zoom lens, theoperation of the second stepping motor 70 can be controlled so that theretracting operation of the zoom lens 10 starts at the angular positionθ2 and is completed at the angular position θ3.

In each of the above described first and second embodiments of the zoomlenses, the third lens group 13 e, the low-pass filter 13 f and the CCD13 g are held by the common CCD holder 30 to be provided as a unit so asto be moved together in both the image stabilizing operation and theradially retracing operation, in which the third lens group 13 e, thelow-pass filter 13 f and the CCD 13 g are retracted into the retractionspace SP in the housing 11 (and also in the radially advancing operationin which the third lens group 13 e, the low-pass filter 13 f and the CCD13 g are moved to a position on the photographing optical axis Z1 fromthe retraction space SP).

The third lens group 13 e is the rearmost lens group of thephotographing optical system which is positioned immediately in front ofthe aforementioned unit that includes the third lens group 13 e, thelow-pass filter 13 f and the CCD 13 g. The structure of the zoom lens 10which allows the third lens group 13 e (provided as the rearmost lensgroup) and the CCD 13 g to be driven as one body makes it possible todesign the photographing optical system of the zoom lens 10 as animage-side telecentric system, in which the principal ray is parallel tothe lens optical axis at the image side (CCD 13 g side), with noincrease in effective diameter of the third lens group 13 e.

Namely, unlike the above illustrated embodiment of the zoom lens 10,supposing the third lens group 13 e was not moved and only the CCD 13 gwas moved in directions perpendicular to the photographing optical axisZ1 during the operation for image stabilization, it would be necessaryto increase the effective aperture of the third lens group 13 e becausethe entire light-receptive surface of the CCD 13 g and the exit surfaceof the third lens group 13 e have to remain facing each other evenduring movement of the CCD 13 g. Conversely, in the present embodimentof the zoom lens, the effective aperture of the third lens group 13 edoes not have to be increased because the third lens group 13 e and theCCD 13 g are provided as a single unit, movable as one integral body, sothat the positional relationship therebetween does not change.

When the zoom lens 10 changes from the photographic state shown in FIG.2 to the retracted state shown in FIG. 1, the vertical moving frame 36is retracted into the retraction space SP in the housing 11 with the useof a part (the vertical guide shaft 38) of the image stabilizingmechanism. During this retracting operation of the vertical moving frame36, the third lens group 13 e, the low-pass filter 13 f and the CCD 13g, which are held by the CCD holder 30 to be provided as a single unit(retractable optical unit), move together as one integral body.Therefore, the space created on the photographing optical axis Z1 by theretracting movement of the retractable optical unit away from thephotographing optical axis Z1 is greater than that in the case whereonly the CCD 13 g is retracted away from the photographing optical axisZ1, which makes it possible to accommodate another element or elementssuch as the second lens group 13 d in such a space created on thephotographing optical axis Z1 with efficiency (see FIG. 1).

The CCD holder 30 is totally enclosed in a dust-resistant fashion by theuse of the packing 30 b and the low-pass filter 13 f to prevent dustfrom sticking to the light-receptive surface of the image sensor, andthe whole of the CCD holder 30 is moved while maintaining thisdust-resistant structure thereof in both the image stabilizing operationand the radially retracing operation. Therefore, the dust-resistantcapability of the CCD holder 30 does not deteriorate even if the CCD 13g is moved, which makes it possible to ensure a high opticalperformance.

Although the present invention has been described based on the aboveillustrated first and second embodiments, the present invention is notlimited solely to these particular embodiments. For instance, althoughthe above described embodiment is an application to a zoom lens, thepresent invention can be applied to an imaging device other than zoomlens.

Obvious changes may be made in the specific embodiments of the presentinvention described herein, such modifications being within the spiritand scope of the invention claimed. It is indicated that all mattercontained herein is illustrative and does not limit the scope of thepresent invention.

1. An imaging device comprising: a photographing optical systemincluding an image sensor positioned at an imaging position of saidphotographing optical system; and an image stabilizer which detectsvibration applied to said photographing optical system and moves saidimage sensor in a plane orthogonal to an optical axis of saidphotographing optical system to counteract image shake in accordancewith a direction and a magnitude of said vibration, wherein said imagesensor and a rearmost lens group of said photographing optical system,which is positioned in front of said image sensor, are provided as amovable unit so that said image sensor and said rearmost lens group areintegrally moved by said image stabilizer.
 2. The imaging deviceaccording to claim 1, wherein said rearmost lens group and said imagesensor are held by a common holder in a dust-resistant fashion so that adust-resistant space is formed between said rearmost lens group and saidimage sensor with a light-receptive surface of said image sensor beingpositioned in said dust-resistant space.
 3. The imaging device accordingto claim 2, wherein said photographing optical system includes a filterpositioned in said common holder between said rearmost lens group andsaid image sensor.
 4. The imaging device according to claim 2, furthercomprising: a first moving frame which holds said common holder and ismovable linearly in a first direction in said plane that is orthogonalto said optical axis; and a second moving frame which holds said firstmoving frame and is movable linearly in a second direction perpendicularto said first direction in said plane that is orthogonal to said opticalaxis.
 5. The imaging device according to claim 1, further comprising aradially-retracting device which moves said movable unit to aradially-retracted position, at which said movable unit is radiallyretracted away from said optical axis along a direction perpendicular tosaid optical axis beyond a predetermined range of movement of saidmovable unit for image stabilization, when said imaging device changesfrom a photographic state to a non-photographing state.
 6. The imagingdevice according to claim 5, wherein, when said movable unit is at saidradially-retracted position, another optical element of saidphotographing optical system enters a space in which said movable unitis positioned when at a photographing position at which said movableunit is located on said optical axis in said photographic state.
 7. Theimaging device according to claim 6, wherein said another opticalelement is positioned in front of said movable unit on said optical axisin said photographic state.
 8. An imaging device comprising: aphotographing optical system including an image sensor positioned behinda rearmost lens group of said photographing optical system, saidrearmost lens group and said image sensor being provided as a movableunit so that said image sensor and said rearmost lens group areintegrally movable in a plane orthogonal to an optical axis of saidphotographing optical system; a detector for detecting vibration appliedto said photographing optical system; and an actuator which moves saidmovable unit in said plane to counteract image shake in accordance witha direction and a magnitude of said vibration detected by said detector.